Grand average ERP waveforms time-locked to target onset in Experiment 2.

<p>The depicted waveforms represent ERPs for the pool of O1/O2/PO7/PO8 electrodes, as a function of cue validity (solid lines: valid trials; dashed lines: invalid trials) and instruction (black: human-controlled, gray: pre-programmed). The two types of targets (F and T) as well as left/right sides of visual field were averaged together. The displayed ERPs are the subtracted waveforms (target present-target absent) and filtered with a 30-Hz high-cutoff filter (Butterworth zero phase, 24 dB/Oct) for illustration purposes.